My Minitrix cleaner is permanently wired to the lighting power supply, 10 volts, and covered with a small shed. Lift the shed, clean the wheels, put the shed back. It can't get lost, is solidly mounted, and is safe to use with my Nn3 motors as well as the standard gauge.
The shed is next to the transfer tracks, so both gauges run right by it, and covered nobody knows it's there.
It doesn't seem to have done any damage to wheels in the few years I've had it.